First, the surface of the handles before they are anodized represents the most significant factor. If the handles are a little rougher to start with, they will stay that way or get worse. If the handles are smoother, they can get rougher, but typically will continue to be better after the process as well.
It would not be surprising if there were some pretty noticable variations regarding both the color and texture of the handles. Anodizing aluminum is something that most product shops use relatively simple methods to control and the results have some variation. In particular:
The aluminum is typically cleaned first in a non - etching soap bath, basically using an industrial strength detergent, generally fairly basic (in pH). (This is mostly to degrease, removing hydrocarbons of various types)
After rinsing, they go into an etching bath where the oxide layer is stripped off of the aluminum, so that the anodize layer can be put on in a controlled fashion. Here is where the first real source of variation can happen. The etching solutions are controlled via pH.(this tells you how aggressive the solution is.) From a fresh solution to a solution requiring addition of concentrate the pH can change probably 1 - 2 points. Since the pH scale is logarithmic, this actually can have a noticable effect. As the pH tends toward neutral, the etching is less effective, and the process takes more time. Alot of production shops do not try and closely balance these things, so some things are going to get etched more (and they will seem rougher, because the Aluminum alloy doesn't etch perfectly uniformly) and some things less. Also, many shops do not have automated timers, etc. for these processes, so they can have a tendency toward more approximate times in the solutions.
After etching (and rinsing again) they are anodized. Anodize coating on Aluminum is just a thick oxidation layer - Al2O3, sapphire, whatever you want to call it. It is done by setting up an anode and cathode circuit between a source and the part and running current through it to cause the oxidation. The oxidation is very thin (typically no more than .0005" and often much less depending on spec.) so it will follow the contours of the base surface in detail. Color is typically added in this solution, and depending on the etch, the exact blend of aluminum, current, voltage and time, this will be different. Again, also a fresh colored bath with color differently than one that is close to needed replenishment.
These are the very basics and there are lots of variations, but the upshot is I wouldn't be surprised at all if there were differences. As an aside, the green Scotchbrite pads are in fact made from Aluminum Oxide, the same as the anodize, the red ones are something else, and I'm not sure what - I actually think zinc oxide, but I'm not sure. You need to be a little careful when using them on the anodized surface, because you can take it off, like I said it isn't that thick. One simple way you can check is if you have a multimeter, check the continuity across the sections you are rubbing down. As long as it shows that it still will not close the circuit, you have coating there. If it lets some current through, you are at bare aluminum. (Aluminum Oxide is actually a ceramic so it is an insulator.)
That's probably more than anyone wants to know about anodizing, but what the heck, someone might reference it later. Nice looking knife - I may have to get one!
